Flooded Kansai airport had crucial infrastructure on basement floor

The runways of Kansai International Airport are submerged under seawater after powerful Typhoon Jebi triggered high waves and storm surges on Sept. 4, 2018. (Mainichi)

OSAKA -- Kansai International Airport, which was temporarily shut down recently after it was flooded by a storm surge caused by Typhoon Jebi, had crucial infrastructure like a disaster response center and an electric substation located on the basement floor of the terminal building, an area susceptible to flooding.

All these facilities were immersed in water, leaving passengers ill-informed due to the failing public address system and a large-scale blackout. Experts on disaster prevention have since demanded the "implementation of drastic countermeasures against floods at the airport, like the installation of electrical supply facilities on the upper floors."

According to the operating company, Kansai Airports, three out of six power transformers installed on the first basement floor of the Terminal 1 Building were submerged in seawater and damaged. As a result, electricity failed in most parts of Terminal 1, and the lack of power is still restricting the airport from resuming full operations.

The disaster response center was also exposed to seawater, and equipment for the public address system broke down. Many of those stranded at the airport were not updated with information about the operation of boats to evacuate from the isolated airport.

Kansai Airports acknowledged that most of the seawater has been drained from the basement floors of the terminal building, and the cleaning of equipment continues as it determines which facilities need to be repaired.

At a Sept. 8 press conference, Kansai Airports Chief Executive Officer Yoshiyuki Yamaya stated, "Electrical facilities are located on basement floors for the majority of airports and large office buildings in Japan. The elevated seawalls were meant to protect (Kansai Airport) from tsunami and high tides. We could have drained all the water if the drainage pumps had been working, as we do when we receive heavy rain."

Yamaya emphasized that the situation was "beyond expectations," but the flooding of infrastructure equipment can have horrific results. The Fukushima No. 1 Nuclear Power Plant disaster following the Great East Japan Earthquake on March 11, 2011, was the result of a tsunami-damaged emergency diesel generator that failed to cool the reactor.

Meanwhile, Chubu Centrair International Airport, based in Aichi Prefecture on a man-made island just like Kansai Airport, has a seawall standing 3.8 to 5.8 meters above the average sea surface height, but up to six-meter-high tsunami waves caused by a feared Nankai Trough earthquake in central to southern Japan are predicted to hit the airport. Central Japan International Airport Co., which operates Centrair, explained it is "formulating an evacuation plan on the basis that tidal waves and tsunami are going to sweep over the seawalls." Movable storm surge barriers have been set up at the entrances of important facilities such as those which store electrical equipment on the first floor. There are evacuation route signs in the passenger terminal with directions leading to the upper floors, and tsunami sirens are located outdoors.

Toshitaka Katada, a specially appointed professor at the Graduate School of Interdisciplinary Information Studies, specializing in disaster-related social engineering, pointed out that, "Kansai airport has been sinking as it is on the sea (artificial island), and the risk of flooding was predictable. There is a problem in the airport operator's crisis management to place crucial infrastructure, like electrical equipment which is vulnerable to water, on the basement floor."